JP2016141233A - Vehicle driving support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress that a regular reflection component of a laser beam which forms a light pattern projected on a road surface dazzles a driver of another vehicle when the road surface gets wet on rainy day.SOLUTION: A vehicle driving support device which is mounted on a vehicle and displays a prescribed light pattern for being recognized by a driver of the own vehicle or another vehicle, a pedestrian and an environmental circumstance detector on a road surface around the own vehicle includes: a road surface projection optical system which scans a light source beam with use of radiation light from a coherent light source, outputs a projection beam and projects the light pattern to the road surface around the own vehicle; a road surface wetting information retention means which retains information whether the road surface around the own vehicle gets wet or not; and a control circuit. Therein, during a period in which the road surface wetting information retention means retains such information that the road surface around the own vehicle gets wet, the control circuit controls such that an incident angle for the road surface is made shallow and the outputting of the projection beam for projecting the light pattern toward the neighborhood of boundary of a travelling zone on which the own vehicle travels is stopped.SELECTED DRAWING: Figure 1

Description

  The present invention scans radiation emitted from a coherent light source such as a semiconductor laser, draws a predetermined light pattern on the road surface around the host vehicle, and draws it on the driver, pedestrian, and environmental conditions of the host vehicle or other vehicles. The present invention relates to a vehicle driving support device that enables a detector to recognize and contribute to traffic safety.

  With respect to the prior art in which a light pattern is displayed on the road surface around the host vehicle using a laser beam such as a semiconductor laser and is recognized by a driver, a pedestrian, or an environmental condition detector of the host vehicle or another vehicle, for example, No. -238307 irradiates a road surface position that is a predetermined distance away from the front of the vehicle with a visible spot marker or a polygon such as a polygon by scanning using a two-dimensional galvanometer. It describes what allows the driver to recognize the presence of the host vehicle.

Japanese Patent Laid-Open No. 2003-231450 should acquire a light pattern formed on a road surface by a laser beam emitted by the own vehicle and other vehicles by an imaging device and pay attention to the progress of the own vehicle based on the information. What determines the state is described.
In this technology, when the traveling track estimated to travel by the host vehicle is calculated based on the vehicle speed, the amount of motion state, the steering angle, and the steering force of the host vehicle, The left and right boundary lines between the part that passes through and the part that does not pass through are calculated, and the part of the boundary line that is necessary for safety depending on the speed is scanned by the laser actuator and drawn. .

  Furthermore, in Japanese Translation of PCT International Publication No. 2004-526612, a light pattern is displayed on the road surface behind the host vehicle by a method used in the field of lighting effects for a spectacle show, in case of an accident or emergency stop. , What provides information to subsequent vehicles is described.

In the technique just described, it is assumed that the laser beam forming the light pattern projected on the road surface is diffusely reflected on the road surface and diffused almost uniformly in all directions without depending much on the incident direction of light. .
However, when the road surface is wet due to rain, especially for light rays with a small incident angle to the road surface (the angle at which the light beam forms with the road surface is small), this assumption does not hold, and the specular reflection component is dominant. If the specular reflection component of the laser beam that forms the light pattern projected on the road surface accidentally hits the driver's eyes directly on the oncoming vehicle, the driver will be strongly dazzled, causing a traffic accident. Concerned.

In order to deal with such a dazzling problem, for example, Japanese Patent Application Laid-Open No. 2003-231438 discloses a road surface irradiated with a laser beam that forms a light pattern projected on the road surface in consideration of a wet road surface. Is described in which, when a pedestrian that is an obstacle is detected based on the contrast of an image captured by the imaging device, a visible light beam is irradiated while avoiding this.
However, in the case of this technology, only pedestrians are protected from dazzling, and the problem of dazzling for drivers of other vehicles such as oncoming vehicles still remains unsolved.

In addition, in Japanese Patent Application Laid-Open No. 2003-285585, in consideration of the case where the road surface is wet, a glass plate forming a Brewster angle is inserted into the beam from the semiconductor laser so that the road surface is parallel to the road surface. Since the polarized light component is reflected and removed by the glass plate, the laser beam that forms the light pattern projected on the road surface does not cause strong regular reflection even on wet road surfaces, causing dazzling to pedestrians and drivers of other vehicles. It states what claims to be able to solve the problem.
However, the Brewster angle is an angle that allows 100% transmission of P-polarized light and is not an angle that reflects 100% of S-polarized light. For example, the Brewster angle of water is about 53 degrees, that is, The angle formed by the light beam with the road surface is about 37 degrees. When the light beam angle is shallower than this, the reflection increases rapidly even in the P-polarized wave, and the road surface wet with rain is not flat. Except when displaying a light pattern at a very close distance that is projected by a laser beam having an angle (nearly 90 degrees that the light beam forms with the road surface), the laser beam that forms the light pattern projected on a relatively far road surface is at least Since a strong specular reflection is partially generated, the problem of dazzling the driver of another vehicle cannot be solved only by making the beam P-polarized.
Incidentally, since a normal semiconductor laser originally oscillates with a linearly polarized wave, it is only necessary to arrange the semiconductor laser so as to be a P polarized wave with respect to the water surface of a wet road surface without inserting a glass plate.

Although it is not a technique for drawing a predetermined light pattern on the road surface around the host vehicle and causing it to be recognized by a driver, a pedestrian, or an environmental condition detector of the host vehicle or another vehicle, as in the present invention, Japanese Laid-Open Patent Publication No. 2011-157022 discloses a vehicle headlamp capable of dynamically generating a desired light distribution pattern by scanning a semiconductor laser beam while modulating the intensity thereof. As the light distribution pattern, a pattern that dimmes or extinguishes a region closer to the normal low beam light distribution pattern is described.
Since this is a headlamp and scans a wide range, as described in the publication, even if the laser light is incident on the human eye, the time is short and adverse effects on the eye are suppressed. .
For this reason, it is reasonable to simply dim the near area.
However, extinguishing a nearby area entails a problem that the risk of causing an accident in which the vehicle comes into contact with a pedestrian or an obstacle increases, and as a compensation for consideration of the dazzling of the driver of the oncoming vehicle. The balance is greatly diminished, and it cannot be said that this technology can be adopted.

JP 05-238307 A JP 2003-231450 A Special table 2004-526612 JP 2003-231438 A JP 2003-285658 A JP2011-157022

  The problem to be solved by the present invention is to suppress the specular reflection component of the laser beam that forms the light pattern projected on the road surface from dazzling other vehicle drivers when the road surface is wet in the rain. An object of the present invention is to provide a vehicle driving support device.

  According to a first aspect of the present invention, there is provided a vehicle driving support apparatus that includes a predetermined light pattern (Q) that is mounted on a vehicle and is recognized by a driver, a pedestrian, or an environmental condition detector of the host vehicle or another vehicle. A vehicle driving support device for displaying on a road surface around a host vehicle, wherein a coherent light source (Ds) and a light source beam (Fb) emitted from the coherent light source (Ds) are scanned to output a projection beam (Fo) The road surface projection optical system (Up) that projects the light pattern (Q) onto the road surface around the host vehicle, and the road surface wet water information holding means (Uw) that holds information about whether or not the road surface around the host vehicle is wet. ) And a control circuit (Ec) for controlling the coherent light source (Ds) and the road surface projection optical system (Up), and the road surface wet water information holding means (Uw) wets the road surface around the host vehicle. Information to the effect During this period, the control circuit (Ec) has a small incident angle with respect to the road surface, and the projection beam (Fo) that projects the light pattern (Q) toward the vicinity of the boundary of the traveling zone where the host vehicle travels. Control is performed to stop the output.

  In the vehicle driving support apparatus according to the second aspect of the present invention, during the period in which the road surface wet water information holding means (Uw) holds information that the road surface around the host vehicle is wet, the control circuit (Ec) The output of the projection beam (Fo) for projecting the light pattern (Q) to the road surface ahead of the following vehicle traveling in the same traveling zone as the traveling zone of the host vehicle is controlled. Is.

  In the vehicle driving support apparatus according to the third aspect of the present invention, the road surface wet water information holding means (Uw) detects whether the road surface around the own vehicle is wet, and the road surface around the own vehicle is A road surface wet water detector (Xw) for generating a road surface wet water detection signal (Sw), which is information on whether or not the vehicle is wet, is provided.

  To provide a vehicle driving support device that suppresses the specular reflection component of a laser beam that forms a light pattern projected on a road surface from being dazzling to a driver of another vehicle when the road surface is wet due to rain. it can.

The block diagram which simplifies and shows the vehicle driving assistance device of this invention is represented. The schematic diagram which simplifies and shows one form of the one part of the Example of the vehicle driving assistance device of this invention is represented. The schematic of the concept relevant to the technique of the vehicle driving assistance device of this invention is represented.

First, the configuration will be described with reference to FIG. 1, which is a simplified block diagram of the vehicle driving support device of the present invention.
Radiation light (Fs) from a coherent light source (Ds) is converted into a light source beam (thickness suitable for being projected far away by a conversion optical system (Bc) inserted as necessary, such as a collimator lens or a beam expander. Fb) and input to the road surface projection optical system (Up).
As the coherent light source (Ds), for example, a semiconductor laser or a light source that converts the wavelength of the emitted light of the semiconductor laser using a nonlinear optical phenomenon such as harmonic generation or optical parametric effect can be used.

In the road projection optical system (Up), for example, two optical deflection elements such as an acoustic light deflection element (AOD) and a galvanometer mirror are arranged so that their deflection directions are orthogonal to each other, and each is independently driven and controlled. Thus, a two-dimensional deflector that can emit an incident beam in an arbitrary direction is provided.
In the case of a galvanometer mirror, the deflection angle of each of the two optical deflection elements is defined by the magnitude of the drive current that flows through the coil. In the case of an acousto-optic deflection element, the frequency of the high-frequency drive voltage applied to the ultrasonic transducer. It is prescribed by.
The light source beam (Fb) input to the road surface projection optical system (Up) is deflected in the direction of azimuth angles θ and ψ and emitted to the outside of the vehicle driving support device (Uf). The beam spot (P) is formed by reaching the road surface around the host vehicle, but the beam spot (P) moves continuously by dynamically changing the azimuth angles θ and ψ. An arbitrary light pattern (Q) such as a curve, a circle, a polygon, or a character can be projected on the road surface around the host vehicle.

Here, for convenience of future explanation, the azimuth angles θ and ψ described above in this specification are defined.
With this vehicle driving support device mounted on a vehicle, the vehicle is traveling in the straight direction and the depression angle is the angle in the vertical plane of the deflected beam with the axis parallel to the flat road surface as the z-axis That is, the angle formed by the light beam with the road surface is written as θ, the angle in the horizontal plane is written as ψ, and both θ and ψ are called azimuth angles.

The control circuit (Ec) modulates the input power to the coherent light source (Ds) via the light source modulation signal (Ss), controls lighting or extinguishing, and controls the brightness at the time of lighting.
Furthermore, the control circuit (Ec) transmits the target values θp and ψp of the azimuth angles θ and ψ to the road surface projection optical system (Up) via the azimuth angle target signal (Sp), and the road surface projection optical system ( The drive circuit included in Up) controls the drive current and drive voltage of each optical deflection element so that the azimuth target values θp and ψp are realized.

On the other hand, the road surface wet water information holding means (Uw) outputs a road surface wet water detection signal (Sw) which is information indicating that the road surface around the host vehicle is wet.
Note that a method for acquiring information on whether the road surface around the own vehicle is wet by the road surface wet water information holding means (Uw) will be described later.
The control circuit (Ec) is in the period when the road surface wet water detection signal (Sw) is active, that is, when the road surface around the host vehicle is wet, the coherent light source (Ds) or the The projection beam that projects the light pattern (Q) by controlling the road surface projection optical system (Up) or both so that the incident angle with respect to the road surface is shallow and the vicinity of the boundary of the traveling zone in which the host vehicle travels. The output of Fo) is stopped.

Here, as a reference for determining that the incident angle with respect to the road surface is shallow, a model in which the road surface is simplified to be a flat water surface is considered, and the projection beam (Fo) is P-polarized with respect to the water surface. When configuring the vehicle driving support device, the lower limit of the angle θ formed by the light beam with the road surface is, for example, about 11.2 degrees where the reflectance is 20%, or about 8.5 degrees where the reflectance is 30%. be able to.
However, since rainwater collected on the road surface is not pure water, oil films are often floating, and it is not flat, so it is clear that road surface reflectance is not a simple function of only θ. , Θ are the same, but differ for each part of the road surface.
Therefore, even if an acceptable road surface reflectance is determined, the lower limit value of the angle θ formed by the light beam to determine that the incident angle with respect to the road surface is shallow cannot be uniquely determined from theoretical considerations. It is more reasonable to make a decision.

Incidentally, the reflectance value described above can be easily calculated by obtaining a well-known Fresnel coefficient.
Specifically, when the angle formed between the normal of the water surface and the light beam, that is, the incident angle φ (where φ = 90−θ) is determined, the refraction angle χ is obtained through the value 1.333 of the refractive index n of water. , The following formula
sinχ = sinφ / n
Therefore, the power reflectivity (the square of the Fresnel coefficient, which is the amplitude reflectivity) is expressed by the following formula: R = {tan (φ−χ) / tan (φ + χ)} ^ 2
It can be calculated with
However, the symbol ^ 2 represents the square.

As a control method in which the control circuit (Ec) stops the output of the projection beam (Fo) for projecting the light pattern (Q), for example, the simplest is whether or not the road surface around the host vehicle is wet. Is controllessly controlling the road surface projection optical system (Up) and the coherent light source (Ds), and the projection content is a light pattern for the vicinity of the boundary of the traveling zone in which the host vehicle travels, and θ or θp is When it is below the lower limit value and the road surface wet water detection signal (Sw) is active, additional control may be performed to turn off the coherent light source (Ds).
However, in the case of such a simple control, the road surface projection optical system (Up) moves wastefully even during a period when the coherent light source (Ds) is turned off by additional control. By performing control so as to omit the control sequence portion from when θp becomes equal to or lower than the lower limit value until the next lower limit value is exceeded, the above-mentioned useless movement can be avoided.

In addition, the above-mentioned traveling zone is a region where the vehicle body of the vehicle at a certain moment is projected on the road surface, is moved with the traveling of the vehicle, and is a region formed by summing and cumulatively combining, This refers to the area with a margin in the width direction necessary for safety.
Therefore, for example, when the vehicle travels along the vehicle traffic zone, the travel zone and the vehicle traffic zone are substantially the same unless the width of the vehicle traffic zone is excessively wide.
However, when changing lanes or turning left and right, the vehicle will cross the boundary of the vehicle lane, so in the period from the start to completion of those actions, the driving zone is different from the vehicle lane, It needs to be interpreted according to the area just described.
Similarly, in a place where a vehicle traffic zone based on road markings is not set, it is necessary to interpret it according to the area just described.

Here, the conditions for stopping the output of the projection beam (Fo) that projects the light pattern (Q) are as follows: the incident angle with respect to the road surface is shallow, and the light pattern is projected in the vicinity of the boundary of the traveling zone where the host vehicle is traveling. The reason for the case will be described.
First, considering the case where the incident angle with respect to the road surface is deep, the reflectance is low and the specular reflection component escapes to the sky, so the oncoming vehicle, the preceding vehicle and the following vehicle traveling in the same direction, the left or right It can be understood that the driver of the vehicle traveling forward or backward is not dazzled and thus can be removed from the conditions.

  Next, when the projection target is not in the vicinity of the boundary of the traveling zone in which the host vehicle travels, for example, when there is a light pattern to be projected in the vicinity of the direction of ψ = 0 during straight traveling, firstly, When the preceding vehicle is close, the downward projection beam only hits the body of the preceding vehicle, and secondly, when the preceding vehicle is a little away and the projection beam is reflected by the wet road surface in front of the own vehicle, Even if the reflected light hits the vehicle body and enters the vehicle from the rear window, the light is upward, so it only hits the ceiling, including when it is reflected by the room mirror. Third, the preceding vehicle When far away, specularly reflected light reflected on a wet road surface may enter the driver's eyes via the rear-viewer's room mirror, but it is weak enough because it is far away. Even so, driving the preceding vehicle Without is possible to give a dazzling to, therefore, it can be seen that the Hazuseru from the condition.

In addition, the projection of the light pattern as just described is an environmental condition detector, that is, the reflected scattered light is acquired as an image with an imaging device, for example, and the reflected scatterer is a road surface or a preceding vehicle or When using this vehicle driving support device together with a detector that identifies whether it is an obstacle and extracts information on the safety status of the environment ahead of the host vehicle, it is a projection of a light pattern necessary to ensure safety .
According to the present invention, even when it is raining, there is no need to stop the output of the projection beam (Fo) for the environmental condition detector, and there is a great advantage that safety is ensured.

  As described above, according to the vehicle driving support device of the present invention, the emitted light from the coherent light source such as a semiconductor laser is scanned, and a predetermined light pattern is drawn on the road surface around the own vehicle. Makes it possible for drivers, pedestrians, and environmental condition detectors of the vehicle or other vehicles to recognize and contribute to traffic safety, and the light pattern projected on the road surface when it is wet in the rain Since the specular reflection component of the laser beam to be formed can prevent the driver of another vehicle from being dazzled, the occurrence of a traffic accident caused by dazzling can be prevented.

However, even when the projection target is not in the vicinity of the boundary of the traveling zone in which the host vehicle travels, in the rainy weather, the light pattern is formed on the road surface in front of the following vehicle traveling in the same traveling zone as the traveling zone in which the host vehicle travels. It is desirable to stop the output of the projection beam (Fo) that projects (Q).
The reason is that the specularly reflected light from the road surface in this situation is highly likely to directly hit the eyes of the driver of the following vehicle.
By the way, the projection of the light pattern as described above, for example, displays a mark indicating the limit position of the inter-vehicle distance according to the traveling speed on the road surface so that the driver of the following vehicle can recognize it, and the rear-end collision This is useful for applications that are intended to prevent this.

Regarding the realization of the road surface wet water information holding means (Uw), it is most certain to provide a dedicated road surface wet water detector (Xw).
An example of a specific configuration of the road surface wet water detector (Xw) will be described. For example, a light beam having an appropriate wavelength is irradiated obliquely with respect to the road surface, and the intensity of the specular reflection component light. And the road surface wet water detection signal (Sw), which is information indicating that the road surface around the host vehicle is wet, is output when the ratio of the intensity of the specularly reflected component light to the irradiated light beam is equal to or greater than a specified value. Configure.
What is necessary is just to install the road surface wet water detector (Xw) of the form just described in the location which faces the road surface of the vehicle body lower surface of the own vehicle.
Further, an electrical circuit element whose electrical parameters such as conductivity and capacitance change when wet is installed on the roof of the host vehicle, for example, and whether the electrical parameter value exceeds a prescribed threshold value or not. You may make it generate | occur | produce a road surface wet water detection signal (Sw) using the precipitation sensor which detects the presence or absence of precipitation.

Further, a test light pattern is projected onto a specific portion of the road surface around the host vehicle by the road surface projection optical system (Up) of the vehicle driving support device, and the reflected scattered light is provided as an image with an image sensor, for example. The road surface wet water detection signal (Sw) may be generated by image acquisition and image analysis. Here, as the specific portion described above, the projection with a shallow incident angle with respect to the road surface in the vicinity of the direction of ψ = 0. It is preferable to use a beam (Fo) for projecting a beam (Fo) in order to eliminate the possibility of dazzling other vehicle drivers due to the test light pattern.
Or, as will be described later, without using an image sensor, a component of the backscattered light on the road surface of the projection beam (Fo) returning to the road surface projection optical system (Up) is detected, There is also a method in which the road surface wet water detection signal (Sw) is generated according to the strength.

Instead of realizing the road surface wetting water information holding means (Uw) by providing the dedicated road surface wetting water detector (Xw) as described above, as a simpler realizing method, for example, a wiper is used. When the switch to be operated is turned on, the road surface wet water detection signal (Sw) may be output.
Alternatively, the driver himself determines whether or not the road surface around the vehicle is wet. If the driver determines that the road surface is wet, the switch for outputting the road wet water detection signal (Sw) is manually turned on. It is good to do.

Here, one point is supplemented about the fundamental matter.
Even if there is a problem that the projection beam that projects at a shallow angle on the road surface in rainy weather has the side effect of dazzling the driver of the opposing vehicle, it may be better not to stop the output to ensure safety, However, the projection beam under such conditions does not form a light pattern that can be effectively recognized by humans and environmental condition detectors on the road surface (the irradiation point when the laser pointer is irradiated is It can be easily understood from the experience that it can be seen by hitting it on white paper, but it can not be seen by hitting it on a mirror surface), so there is no safety given to the vehicle even if it is output, simply escaping to the sky or other Either hitting the vehicle ends up unnecessarily or increasing the risk of oncoming vehicle accidents with the side effect of dazzling, so it is best to stop the output for the projection beam under the above conditions. In it, it can be said that.
Naturally, the safety that would have been imparted by light pattern projection if it was not raining would not be imparted when it was raining. Therefore, if you want to compensate for the reduced safety, it is effective separately from the present invention. It is necessary to take appropriate measures.

In the following, embodiments of the present invention will be described.
First, referring to FIG. 2 which is a schematic diagram showing a part of an embodiment of the vehicle driving support apparatus of the present invention in a simplified manner, the coherent light source (Ds) configured using a galvanometer mirror and the above-mentioned The optical system combined with the road surface projection optical system (Up) will be described.
Radiated light from a coherent light source (Ds) by a semiconductor laser is converted into a parallel light source beam (Fb) via a conversion optical system (Bc) as a collimator using an aspheric lens, and a polarization beam splitter, which will be described later. Via (Bs), it is incident on the rotating mirror (Gr1) of the θ deflection galvanometer mirror (G1).
The rotary mirror (Gr1) is fixed to an actuator shaft (Gz) that reciprocally rotates by driving of the actuator (Ga), and is driven from the drive circuit (not shown) to the actuator based on the control of the control circuit (Ec). The azimuth angle θ after deflection is controlled by the drive current that flows through (Ga).

The beam reflected by the rotating mirror (Gr1) has the same structure as the θ-deflection galvanometer mirror (G1), except that the ψ-deflection galvanometer mirror (G2) has an actuator axis orthogonal to the actuator axis (Gz). Similarly, the azimuth angle ψ after deflection is controlled.
The beam reflected by the rotating mirror (Gr2) of the ψ deflection galvanometer mirror (G2) is emitted from the road surface projection optical system (Up) as the projection beam (Fo), and is arbitrary in the solid angle region (A). The light pattern (Q) can be projected on the road surface around the host vehicle by being two-dimensionally deflected in the direction.
In addition, as the place where the optical system of this figure is installed in the vehicle, it is preferable to have two places on the left and right ends of the upper side of the windshield in the cab and see through the front road surface. This may be one part of the gap between the windshield and the rear mirror.

Incidentally, in the case of a galvanometer mirror, since the magnetic movable part including the mirror has a moment of inertia with respect to rotation, for example, when the drive current is changed stepwise in order to jump the azimuth coordinates θ, ψ, The current value and the azimuth angles θ and ψ do not correspond instantaneously, and θ and ψ rise only at a finite speed and show a behavior that gradually approaches a steady value while ringing (damped oscillation).
Therefore, θ, ψ is detected and PID feedback control is performed to improve the response speed, or during the period when ringing or overshoot occurs, the coherent light source (Ds) is transmitted via the light source modulation signal (Ss). Is turned off to make the unnecessary locus of the beam spot (P) invisible.
In this way, when the azimuth angles θ, ψ are driven to be gradually changed in order to project straight lines or curves instead of jumping and moving the azimuth coordinates θ, ψ, the ringing described above is unlikely to occur. However, an error occurs between the azimuth target values θp, ψp and the azimuth angles θ, ψ due to the operation delay, and as a result, errors in the position and shape of the light pattern (Q) occur, and thus correction processing is necessary. .

Previously, a plurality of examples of the configuration method of the road surface wetting water detector (Xw) that generates information on whether or not the road surface around the host vehicle is wet have been described, but FIG. 2 illustrates the projection beam (Fo). A configuration for realizing a road surface wetting water detector by detecting a component of the back scattered light on the road surface returning to the road surface projection optical system (Up) is depicted.
As described above, since it is preferable to configure the vehicle driving support apparatus so that the projection beam (Fo) is P-polarized with respect to the water surface, the polarization of the projection beam (Fo) is θ in the figure. If the coherent light source (Ds) is arranged so as to be parallel to the direction, and the polarizing beam splitter (Bs) is arranged so as to be adapted thereto, ideally approximately 100 of the light source beam (Fb). % Is reflected toward the rotating mirror (Gr1).
When the projection beam (Fo) hits the road surface to generate backscattered light, the polarization plane generally rotates, so this scattered light returns from the road surface via the rotary mirror (Gr2) and the rotary mirror (Gr1). In this case, the component that has become S-polarized light with respect to the road surface is transmitted through the polarization beam splitter (Bs), and can be detected by the optical sensor (Bx).

For example, if the weak transmitted light of the light source beam (Fb) in the polarization beam splitter (Bs) can be detected by an optical sensor (not shown), the light source beam intensity can be monitored constantly.
By experimentally determining the threshold value of the ratio of the detection amount of the light sensor (Bx) to the light source beam intensity for distinguishing between the case where the road surface is dry and the case where the road surface is wet, this configuration is determined. It can function as a road surface wet water detector, and the road surface wet water detection signal (Sw) can be generated.

In order to avoid the influence of disturbance light such as road illumination light such as sunlight or street light or light emitted from other vehicles, a narrow band filter (Bf) using an interference filter or the like is used as the optical sensor (Bx). It is preferable to put it in front.
Further, in order to enhance the ability to avoid the influence of disturbance light, amplitude modulation of an appropriate frequency is added to the driving current of the coherent light source (Ds), and the amplitude modulation among the detection signals of the photosensor (Bx) is added. Based on the signal that has passed through the electrical narrow band filter that matches the frequency, the road surface wet water detection signal (Sw) is generated, and further using the technique of synchronous detection and lock-in amplification circuit, the detection accuracy It is possible to devise so as to generate the road surface wet water detection signal (Sw) with an increased height.
Further, if the detection signal can be acquired normally and the phase delay of the detection signal with respect to the modulation signal can be measured, the distance between the point where the projection beam (Fo) hits the road surface and the own vehicle is estimated. It becomes possible.

Next, an embodiment of the present invention will be described with reference to FIG. 3 which is a schematic diagram of a concept related to the technology of the vehicle driving support apparatus of the present invention.
The figure shows the current position (Y) and future position (Y ') of the vehicle, and the future position (Y ") ahead. The area between two two-dot chain lines is the moment An area formed by moving the vehicle body of the host vehicle on the road surface as the vehicle travels and combining and accumulatively combining, that is, representing the own vehicle occupied road surface locus, and 2 The area between the broken lines of the book represents an area where a margin in the width direction necessary for safety is added to the above-described own vehicle occupied road surface trajectory, that is, a traveling zone.
However, (a) in the figure depicts a case where the vehicle travels straight, and (b) depicts a case where the course is bent to the left.
For reference only, (a) also shows a vehicle lane boundary road marking (L). For (b), there is a case where the vehicle travels along a vehicle traffic zone boundary road marking that curves to the left, and a case where a lane is changed across the vehicle traffic zone boundary road marking, in order to avoid making the figure complicated. The drawing of road markings for vehicle lanes is omitted.

The vehicle driving support system installed in the vehicle includes the current steering angle by the driver and the change speed of the steering angle by the steering wheel operation, the acceleration of the current vehicle speed and the accelerator operation, and the front of the vehicle obtained using the image sensor. By simulating the position and orientation of the vehicle on the road surface every moment to the near future with the aid of analysis on the road conditions, the shape of the traveling zone can be determined, and the vehicle or other vehicle The shape of the light pattern to be projected in the vicinity of the boundary of the travel zone in which the host vehicle travels is determined so as to be recognized by the driver, the pedestrian, and the environmental condition detector.
Here, the light pattern to be projected may be the boundary line of the traveling zone itself.
However, how far the light pattern should be projected depends on the speed of the host vehicle. The higher the speed, the farther the focus of the light pattern to be projected is.

The vehicle driving support system converts the information representing the shape of the projected light pattern from the plane coordinates on the road surface to the azimuth coordinates θ, ψ, for example, to the control circuit (Ec) of the vehicle driving support device of the present invention. Data is transmitted as an array of azimuth target values θp, ψp.
The control circuit (Ec) repeatedly reads out the received array of azimuth target values θp and ψp, generates the light source modulation signal (Ss) and the azimuth target signal (Sp), and generates the coherent light source (Ds). And the road surface projection optical system (Up).

  However, when the road surface wet water information holding means (Uw) holds information that the road surface around the host vehicle is wet, that is, when the road surface wet water detection signal (Sw) is active, The portion of the array of θp and ψp having θp lower than the lower limit of the angle θ formed by the light beam for determining that the incident angle with respect to the road surface is shallow is the road surface projection optical system (Up). In the period indicated by, the control circuit (Ec) controls the light source modulation signal (Ss) so that the coherent light source (Ds) is turned off, so that the incident angle with respect to the road surface is shallow and the host vehicle is traveling. The output of the projection beam (Fo) for projecting the light pattern (Q) toward the vicinity of the boundary of the traveling zone to be stopped is stopped.

Here, whether the projected beam of the left or right of the light pattern located near the boundary of the traveling zone in which the vehicle is traveling and the vehicle is wet and θ is below the lower limit should be stopped depends on the situation. It is necessary to decide accordingly.
If the vehicle is left-hand traffic, the outside of the left boundary of the driving zone is the end of the roadway (sidewalk or roadside belt), or the vehicle traffic zone traveling in the same direction, not the vehicle traffic zone of the oncoming vehicle, When the track is straight or bent to the left, it is not necessary to stop the projection beam that projects the light pattern near the boundary on the left side of the traveling zone even if the road surface is wet and θ is below the lower limit. .
(However, if it is determined that dazzling to pedestrians should be avoided, the projection beam is also stopped under this condition.)

However, when the path is bent to the right, the specular reflection light on the wet road surface may directly hit the eyes of the driver of the oncoming vehicle, so a light pattern near the boundary on the left side of the traveling zone is projected. The projection beam needs to be stopped.
On the other hand, since the outside of the right boundary of the traveling zone may be a vehicle traffic zone of an oncoming vehicle, the road surface is wet regardless of whether the vehicle is going straight or bent to the left or right. When θ is below the lower limit, it is necessary to stop the projection beam that projects the light pattern near the right boundary of the traveling zone.

  The present invention scans radiation emitted from a coherent light source such as a semiconductor laser, draws a predetermined light pattern on the road surface around the host vehicle, and draws it on the driver, pedestrian, and environmental conditions of the host vehicle or other vehicles. The present invention can be used in an industry that designs and manufactures a vehicle driving support device that aims to make a detector recognize and contribute to traffic safety.

A Solid angle region Bc Conversion optical system Bf Narrow band filter Bs Polarization beam splitter Bx Optical sensor Ds Coherent light source Ec Control circuit Fb Light source beam Fo Projection beam Fs Radiation light G1 θ deflection galvanometer mirror G2 ψ deflection galvanometer mirror Ga actuator Gr1 Rotating mirror Gr2 Rotating mirror Gz Actuator axis L Vehicle traffic zone boundary road marking P Beam spot Q Light pattern Sp Azimuth angle target signal Ss Light source modulation signal Sw Road surface wet water detection signal Uf This vehicle driving support device Up Road surface projection optical system Uw Road surface wet water information holding Means Xw Road surface wet water detector Y Current position Y 'Future position Y "Future position

Claims (3)

A vehicle driving support apparatus that displays a predetermined light pattern (Q) on a road surface around a host vehicle, which is mounted on a vehicle and is recognized by a driver, a pedestrian, or an environmental condition detector of the host vehicle or another vehicle. The coherent light source (Ds) and the light source beam (Fb) by the radiated light from the coherent light source (Ds) are scanned to output a projection beam (Fo), and the light pattern (Q) on the road surface around the host vehicle. Road surface projection optical system (Up), road surface wet water information holding means (Uw) for holding information on whether or not the road surface around the host vehicle is wet, the coherent light source (Ds) and the road surface projection optics A control circuit (Ec) that controls the system (Up), and the road surface wet water information holding means (Uw) holds information indicating that the road surface around the host vehicle is wet. Ec) The vehicle is controlled so as to stop the output of the projection beam (Fo) for projecting the light pattern (Q) toward the vicinity of the boundary of the traveling zone where the vehicle travels. Driving assistance device. During the period when the road surface wet water information holding means (Uw) holds information that the road surface around the host vehicle is wet, the control circuit (Ec) travels in the same traveling zone as the traveling zone where the host vehicle travels. 2. The vehicle driving support device according to claim 1, wherein control is performed to stop the output of the projection beam (Fo) that projects the light pattern (Q) onto a road surface in front of the following vehicle. The road surface wet water information holding means (Uw) detects whether or not the road surface around the host vehicle is wet, and detects the road surface wet water detection signal (information on whether or not the road surface around the host vehicle is wet). The vehicle driving support device according to claim 1, further comprising a road surface wet water detector (Xw) that generates Sw).

Images